U.S. patent application number 10/476129 was filed with the patent office on 2004-07-01 for apparatus and method for the removal of a contaminant from a fluid comprising said contaminant.
Invention is credited to van de Weijer, Franciscus Johannes Maria.
Application Number | 20040124153 10/476129 |
Document ID | / |
Family ID | 19773317 |
Filed Date | 2004-07-01 |
United States Patent
Application |
20040124153 |
Kind Code |
A1 |
van de Weijer, Franciscus Johannes
Maria |
July 1, 2004 |
Apparatus and method for the removal of a contaminant from a fluid
comprising said contaminant
Abstract
The present invention relates to an apparatus (1) for the
removal of a contaminant from a fluid comprising said contaminant,
in particular for the removal of heavy metals from water which is
contaminated by heavy metals, which apparatus (1) comprises a
reaction vessel (2) in which it is intended to treat the
contaminated fluid with a particulate treatment agent (3), which
reaction vessel (2), on its underside, is of substantially conical
design and comprises an inlet (4) for the contaminated fluid which
is to be treated and an outlet for the cleaned fluid. The apparatus
(1) is characterized in that the outlet for cleaned fluid comprises
an overflow (5) and the apparatus (1) being free of mechanical
stirring means which, during use, can come into contact with the
treatment agent (3), and the inlet (4) for contaminated fluid
opening out in the vicinity of the bottom of the reaction vessel
(2), and the apparatus (1) comprising flow-control means (7) in the
inlet (4) for contaminated fluid, all this in such a manner that,
when the apparatus (1) is in use, a dynamic bed of the treatment
agent (3) is created, and that the treatment agent (3), as a result
of a settling action under the influence of the force of gravity,
substantially entirely remains in the reaction vessel (2). The
invention also relates to a method for using the apparatus.
Inventors: |
van de Weijer, Franciscus Johannes
Maria; (Oeffelt, NL) |
Correspondence
Address: |
HOFFMANN & BARON, LLP
6900 JERICHO TURNPIKE
SYOSSET
NY
11791
US
|
Family ID: |
19773317 |
Appl. No.: |
10/476129 |
Filed: |
October 27, 2003 |
PCT Filed: |
April 24, 2002 |
PCT NO: |
PCT/NL02/00273 |
Current U.S.
Class: |
210/688 |
Current CPC
Class: |
B01D 15/02 20130101;
C02F 1/28 20130101; C02F 1/286 20130101; C02F 1/283 20130101; B01J
20/043 20130101; B01D 2215/021 20130101; C02F 2101/20 20130101 |
Class at
Publication: |
210/688 |
International
Class: |
C02F 001/42 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 27, 2001 |
NL |
10117959 |
Claims
1. Apparatus (1) for the removal of a contaminant from a fluid
comprising said contaminant, in particular for the removal of heavy
metals from water which is contaminated by heavy metals, which
apparatus (1) comprises a reaction vessel (2) in which it is
intended to treat the contaminated fluid with a particulate
treatment agent (3), which reaction vessel (2), on its underside,
is of substantially conical design and comprises an inlet (4) for
the contaminated fluid which is to be treated and an outlet for the
cleaned fluid, the outlet for cleaned fluid comprising an overflow
(5) and the apparatus (1) being free of mechanical stirring means
which, during use, come into contact with the treatment agent (3),
and the inlet (4) for contaminated fluid opening out in the
vicinity of the bottom of the reaction vessel (2), and the
apparatus (1) comprising flow-control means (7) in the inlet (4)
for contaminated fluid, all this in such a manner that, when the
apparatus (1) is in use, a dynamic bed of the treatment agent (3)
is created, and that the treatment agent (3), as a result of a
settling action under the influence of the force of gravity,
substantially entirely remains in the reaction vessel (2).
2. Apparatus according to claim 1, characterized in that material
with a particle size of less than 100 .mu.m is substantially
present as treatment agent.
3. Apparatus according to claim 1 or 2, characterized in that in
the reaction vessel (2) there is also a body with an external shape
which is substantially congruent with the internal shape of the
reaction vessel (2) but has smaller dimensions, all this in such a
manner that, as seen from the inlet (4) for contaminated fluid, in
use the speed of displacement of the contaminated fluid is reduced
in the downstream direction.
4. Apparatus according to one or more of claims 1-3, characterized
in that the inlet (4) for contaminated fluid opens out into the
bottom of the reaction vessel (2).
5. Apparatus according to one or more of the preceding claims,
characterized in that the apparatus (1) also comprises an inlet (9)
and an outlet (9) for the treatment agent (3).
6. Apparatus according to one or more of the preceding claims,
characterized in that there are filter means (10) between the
interior of the reaction vessel (2) and the outlet for the cleaned
fluid, for the purpose of retaining any entrained treatment
agent.
7. Apparatus according to one or more of the preceding claims,
characterized in that the flow-control means (7) are able to
generate a pulsed flow of contaminated fluid, preferably in such a
manner that the pulsed flow varies in a range from 80-120%, more
preferably 90-110%, with respect to the nominal flow.
8. Method for the removal of a contaminant from a fluid comprising
said contaminant, in particular for the removal of heavy metals
from water contaminated with heavy metals, using the apparatus
according to one or more of the preceding claims, which method
comprises the steps of introducing a quantity of a particulate
treatment agent into the reaction vessel, bringing contaminated
fluid, which is introduced into the reaction vessel in the vicinity
of the bottom via the inlet for the contaminated fluid, into
contact with the particulate treatment agent, the flow-control
means in the inlet being set in such a manner that the particulate
treatment agent is present in the form of a dynamic bed, that
purified fluid is able to leave the reaction vessel via the
overflow, and that the particulate treatment agent substantially
completely remains in the reaction vessel on account of a settling
action under the influence of the force of gravity.
9. Method according to claim 8, characterized in that the cleaned
fluid is cleaned at least one more time with the aid of an
additional apparatus according to one or more of claims 1-7.
10. Method according to claim 8 or 9, characterized in that the
flow-control means are set in such a manner that a pulsed flow is
obtained, preferably in such a manner that the pulsed flow varies
in a range from 80-120%, more preferably 90-110%, with respect to
the nominal flow.
11. Method according to one or more of the preceding claims 8-10,
characterized in that CaCO.sub.3-containing material is used as
treatment agent.
12. Method according to claim 11, characterized in that milled
shell material is used as the CaCO.sub.3-containing material.
13. Method according to one or more of claims 8-12, characterized
in that the treatment agent substantially comprises material with a
particle size of less than 100 .mu.m.
Description
[0001] The present invention relates to an apparatus for the
removal of a contaminant from a fluid comprising said contaminant,
in particular for the removal of metals and/or heavy metals from
water which is contaminated by metals and/or heavy metals, which
apparatus comprises a reaction vessel in which it is intended to
treat the contaminated fluid with a particulate treatment agent,
which reaction vessel comprises an inlet for the contaminated fluid
which is to be treated and an outlet for the cleaned fluid.
[0002] An apparatus of this type is known, for example from US
patent U.S. Pat. No. 4,156,647. U.S. Pat. No. 4,156,647 describes
an apparatus and a method for the removal of impurities, such as
heavy metals, from fluids, the heavy metals generally being present
in small quantities. According to U.S. Pat. No. 4,156,647, the
fluid which comprises impurities is brought into contact with a
loose, particulate treatment agent, such as milled shells, which is
used to remove the impurity from the stream of fluid by means of a
reaction, ion exchange or adsorption. The treatment material is
retained in the reactor vessel since the wall of the reactor vessel
is provided with a large number of small openings which are each
filled with an inert, compact, finely distributed filter material.
While the apparatus described in U.S. Pat. No. 4,156,647 is
operating, fluid which has been treated. in this way is discharged
via the small openings, while the particulate treatment agent
remains in the reactor vessel. To prevent the openings in the
reactor vessel from becoming blocked, there are means for scraping
the treatment agent off the openings in the reactor vessel provided
on the inside of the reactor vessel.
[0003] One drawback of the abovementioned apparatus is that it has
moving parts, which require a high degree of maintenance.
Furthermore, if a treatment agent with a very small particle size
is used, blockages may easily occur in the openings in the reactor
vessel, so that operation of the apparatus has to be
interrupted.
[0004] The prior art has also disclosed many methods and
apparatuses for removing contaminants using a static bed of
treatment agents. The use of a static bed has various drawbacks,
such as the occurrence of "bypasses", which results in reduced
efficiency of removal.
[0005] It is an object of the present invention to avoid the above
drawbacks and to provide a very simple and efficient apparatus for
the removal of a contaminant from a fluid comprising said
contaminant, and in particular for the removal of (heavy) metals
from water contaminated with (heavy) metals. According to the
present invention, this object is achieved by an apparatus for the
removal of a contaminant from a fluid comprising said contaminant,
in particular for the removal of heavy metals from water which is
contaminated by heavy metals, which apparatus comprises a reaction
vessel in which it is intended to treat the contaminated fluid with
a particulate treatment agent, which reaction vessel, on its
underside, is of substantially conical design and comprises an
inlet for the contaminated fluid which is to be treated and an
outlet for the cleaned fluid, the outlet for cleaned fluid
comprising an overflow and the apparatus being free of mechanical
stirring means which, during use, can come into contact with the
treatment agent, and the inlet for contaminated fluid opening out
in the vicinity of the bottom of the reaction vessel, and the
apparatus comprising flow-control means in the inlet for
contaminated fluid, all this in such a manner that, when the
apparatus is in use, a dynamic bed of the treatment agent is
created, and that the treatment agent, as a result of a settling
action under the influence of the force of gravity, substantially
entirely remains in the reaction vessel.
[0006] The fact that the apparatus according to the invention is
free of mechanical stirring means and is substantially free of
other moving parts which can come into contact with the treatment
agent during use means that the apparatus is very low-maintenance.
The absence of such moving parts also avoids damage thereto, with
all the associated problems.
[0007] A further advantage of the apparatus according to the
invention is that it is very easy to produce at low cost. Also, the
apparatus according to the invention, on account of its simple
design, can be of modular design, can easily be moved and can
therefore be used at any desired location. The apparatus also
comprises a relatively small number of components.
[0008] The fact that the apparatus according to the invention is
operated in a dynamic bed means that there is very efficient
contact between the treatment agent and the contaminated water.
"Dynamic bed" is a term which is known in the specialist field and
therefore requires no further explanation. The dynamic bed provides
that the particles of the treatment agent are not fixed in position
and time.
[0009] It has been found that, if a dynamic bed is not used,
various problems may arise--such as the formation of "bypasses"
which result in less effective removal of contaminants.
[0010] According to the present invention, the underside of the
reaction vessel is of substantially conical design. In this case,
the bottom of the reaction vessel is located in the vertex of the
cone.
[0011] When the apparatus is operating, this improves contact
between the contaminated fluid which is to be purified and the
treatment agent. The treatment agent, once it has been raised
upward, will always move back toward the vertex of the cone at the
bottom of the reaction vessel, i.e. toward the inlet for
contaminated fluid. The person skilled in the art will understand
that, for this purpose, the underside may also be of slightly
parabolic design, provided only that the desired effect is
achieved.
[0012] It is preferable for the treatment agent substantially to
comprise material with a particle size of less than 100 .mu.m. It
has been found that in this way very favourable cleaning results
can be obtained.
[0013] To optimize contact between the treatment agent and the
contaminated fluid when the apparatus is operating, it is
preferable, in this case, if the reaction vessel also contains a
body with an external shape which is substantially congruent with
the internal shape of the reaction vessel but has smaller
dimensions, all this in such a manner that, as seen from the inlet
for contaminated fluid, in use the speed of displacement of the
contaminated fluid is reduced in the downstream direction.
[0014] In this way, an annular passage is formed between the closed
body and the inner wall of the reactor vessel. In practice, it has
been found that this leads to very good mixing of the treatment
agent in the contaminated fluid. Preferably, the body and the
reaction vessel are positioned in such a manner with respect to one
another that the annular channel widens gradually in the downstream
direction.
[0015] It is preferable for the body to be open on the top side and
on the underside, with the result that the treatment agent can
return via the inner side of the body to the underside of the
reaction vessel. If appropriate, flow-influencing means may also be
present at the opening on the underside of the body, in order to
further positively influence the flow profile of the treatment
agent in the reaction vessel.
[0016] It has proven expedient if the inlet for the contaminated
fluid opens out in the bottom of the reaction vessel.
[0017] As a result, when the apparatus is operating, the
contaminated fluid comes into contact with a large proportion of
the treatment agent, since the treatment agent always moves back
toward the underside of the reaction vessel as a result of a
settling action. Therefore, unused treatment agent cannot collect
at the bottom of the reactor vessel, but rather is constantly
entrained by the fluid supplied.
[0018] Furthermore, it is preferable for the apparatus also to
comprise an inlet and an outlet for the treatment agent.
[0019] This makes it easy to renew the treatment agent when it is
found that the cleaning action of the treatment agent is
decreasing. It is also possible, if a particular treatment agent is
required for a particular contaminated fluid, for this particular
treatment agent to be introduced into the reaction vessel in a
simple way.
[0020] Furthermore, it is advantageous if there are filter means
between the interior of the reaction vessel and the outlet for the
contaminated fluid, in order to retain any entrained treatment
agent.
[0021] Although substantially all the treatment agent remains in
the reaction vessel, on account of a settling action, this measure
makes it possible to ensure without any doubt that the cleaned
fluid which is discharged is free of treatment agent.
[0022] Furthermore, it is preferable for the flow-control means to
be able to generate a pulsed flow of contaminated fluid, preferably
in such a manner that the pulsed flow varies in a range from
80-120%, more preferably 90-110%, with respect to the nominal flow.
This makes it easy to form a favourable dynamic bed. The person
skilled in the art will understand that the term "nominal flow" is
understood to mean the mean flow (i.e. 100%).
[0023] Furthermore, the present invention provides a method for the
removal of a contaminant from a fluid comprising said contaminant,
in particular for the removal of heavy metals from water
contaminated with heavy metals, using the apparatus according to
the invention, which method comprises the steps of introducing a
quantity of a particulate treatment agent into the reaction vessel,
bringing contaminated fluid, which is introduced into the reaction
vessel in the vicinity of the bottom via the inlet for the
contaminated fluid, into contact with the particulate treatment
agent, the flow-control means in the inlet being set in such a
manner that the particulate treatment agent is present in the form
of a dynamic bed, that purified fluid is able to leave the reaction
vessel via the overflow, and that the particulate treatment agent
substantially completely remains in the reaction vessel on account
of a settling action under the influence of the force of
gravity.
[0024] In an advantageous embodiment of the method, the cleaned
fluid is cleaned at least one further time with the aid of an
additional apparatus according to the invention.
[0025] In this way, the treatment agents in the separate
apparatuses can be set in such a manner that a specifically
selected impurity, for example, a heavy metal such as hexavalent
chromium which can only be removed under certain conditions, can be
removed.
[0026] It is also possible, by using an additional apparatus, to
provide for preliminary and secondary purification of the
contaminated fluid.
[0027] It is preferable for the flow-control means to be set in
such a manner that a pulsed flow is obtained, preferably in such a
manner that the pulsed flow varies in a range from 80-120%, more
preferably 90-110%, with respect to the nominal flow.
[0028] The treatment agent used is advantageously
CaCO.sub.3--containing material, in particular milled shell
material.
[0029] It has been found that this material achieves very good
cleaning results and, moreover, can easily be obtained in bulk
quantities with a desired particle size.
[0030] According to a preferred embodiment of the method according
to the invention, the treatment agent substantially comprises
material with a particle size of less than 100 .mu.m.
[0031] Using material with a particle size of less than 100 .mu.m
makes it possible to additionally improve the cleaning of the
contaminated fluid.
[0032] According to the invention, the term "treatment agent" is
understood as meaning any material which is suitable for removing
contaminants from the contaminated fluid by a chemical reaction,
ion exchange or adsorption or any other suitable method.
[0033] As has already been stated above, according to the present
invention it is preferable to use milled shell material. Examples
of other suitable treatment agents are activated carbon,
MACROSORB.RTM., chitosan, etc.
[0034] According to the present invention, the term "treat" is
understood as meaning any form of removal or deactivation of the
fluid, for example by reaction, adsorption, absorption, ion
exchange, etc., in such a manner that the contaminant remains in
the reaction vessel with the treatment agent while the cleaned
fluid leaves the reaction vessel via the overflow.
[0035] The person skilled in the art will understand that the
apparatus and method according to the invention are suitable for
both continuous and batch-type processes.
[0036] The present invention will be explained in more detail below
with reference to the appended drawing, in which:
[0037] FIG. 1 shows a diagrammatic cross section through the
apparatus according to the present invention;
[0038] FIG. 2 shows a diagrammatic cross section through an
alternative embodiment of the apparatus according to the invention;
and
[0039] FIGS. 3a-3c show diagrammatic cross sections through
alternative embodiments of the apparatus according to the
invention.
[0040] Identical reference numerals denote identical
components.
[0041] FIG. 1 shows an apparatus 1 for the removal of heavy metals
from water contaminated by heavy metals. The apparatus 1 comprises
a reaction vessel 2 in which it is intended to treat water which is
contaminated with heavy metals using a dynamic bed of particulate
treatment agent 3 which preferably substantially comprises suitable
material with a particle size of less than 100 .mu.m. In the
vicinity of the bottom, the reaction vessel 2 comprises an
optionally pulsed inlet 4 for the water contaminated with heavy
metals which is to be treated and an overflow 5 for the cleaned
water. For this purpose, flow-control means 7, such as a
controllable valve, are present in or close to the inlet 4 for
contaminated water. The bottom of the vessel 2 is of substantially
conical design. The fluid flowing into the reaction vessel 2 itself
represents the driving force for obtaining the desired dynamics of
the treatment agent 3.
[0042] FIG. 2 also shows an apparatus 1 for the removal of heavy
metals, having a reaction vessel 2, the underside of the reaction
vessel 2 once again being of substantially conical design.
Furthermore, the reaction vessel 2 includes a closed body 8 with an
external shape which is substantially congruent with the internal
shape of the reaction vessel 2 but has smaller dimensions. The
internal shape of the reaction vessel 2 and the closed body 8 are
preferably positioned in such a manner that, as seen from the
underside of the reaction vessel 2, there is a widening between
reaction vessel 2 and body 8. This provides in a simple but
effective way for the speed of displacement of the contaminated
fluid to be reduced in the downstream direction. This is explained
in more detail with reference to FIG. 3a-3c. The reaction vessel 2
is also provided with an inlet 6 and an outlet 9 for the treatment
agent 3. Furthermore, there are filter means 10 between the
interior of the reaction vessel 2 and the outlet 5 for cleaned
water, in order to retain any treatment agent 3 which is entrained
while the apparatus 1 is operating.
[0043] In the embodiment of the apparatus 1 according to the
present invention which is illustrated in FIG. 2, the underside of
the reaction vessel 2 is of substantially conical design, and
moreover above this there is an extended top side, with the result
that the zone in which the treatment agent 3 can settle is
increased in size. If desired, the extended top side may be
designed to be vertically adjustable, in which case the correct
height can be selected as a function of, for example, the
sedimentation rate of the treatment agent used.
[0044] When the apparatus 1 shown in FIGS. 1 and 2 is operating,
water which is contaminated with heavy metals is introduced into
the reaction vessel 2 via the inlet 4. Operation of the
flow-control means 7 makes it possible to set a flow profile which
is such that the treatment agent 3 remains below the overflow 5 as
a result of a settling action under the influence of the force of
gravity. The flow-control means 7 may be set in such a manner that
the treatment agent 3 is pushed upward, but not so far that it is
discharged with the cleaned water via the overflow 5.
[0045] The contact between the treatment agent 3, such as for
example milled shell material, and the contaminated water is very
efficient, since treatment agent 3 which is forced upward returns
to the underside of the reaction vessel 2 as a result of a settling
action and via the sloping walls of the reaction vessel.
[0046] In the embodiment which is shown in FIG. 2, contact between
contaminated water and treatment agent, and also the settling
action, are improved by the body 8. If desired, the top side of the
body may be designed in such a manner that any treatment agent 3
which is deposited thereon does not remain in place. This can be
achieved, for example, by providing the body 8 with surfaces which
slope downwards and/or a coating, such as Teflon, on its top side.
Alternatively, the body 8 may be open at its top side, so that the
treatment agent 3 is returned to the bottom via openings or slots
which are present for this purpose (cf. FIGS. 3a-3c). As a result,
the treatment agent 3 is thereby not passivated, but rather
continues to circulate during the treatment process in the reaction
vessel 2.
[0047] If desired, in addition to the flow-control means 7 it is
possible for additional flow-control means (not shown) to be
provided in the vicinity of the inlet 4 for contaminated water, in
order to improve contact between treatment agent 3 and the
contaminated water. Consideration may be given to air-injection or
liquid-injection systems.
[0048] After the contaminated water has been treated with the
treatment agent 3, the cleaned water will be discharged via the
overflow 5 while the treatment agent 3 remains in the reactor
vessel 2 as a result of a settling action. In the embodiment which
is shown in FIG. 2, there is a filter 10 for retaining any reagent
3 which is entrained.
[0049] The overflow 5 of the reaction vessel 2 may be connected to
the inlet of a subsequent reaction vessel (not shown). If desired,
this subsequent reaction vessel may be filled with a different
treatment agent, in order to remove specific heavy metals from the
flow of water. It is also possible for the overflow 5 to be
positioned precisely above the reaction vessel 2, as the highest
point of the apparatus 1. This makes it easy for any trapped air or
other gas which is present to escape from the apparatus 1.
Obviously, the apparatus 1 may also be provided with vent valves
(not shown) to accelerate filling of the reaction vessel 2.
[0050] FIGS. 3a-3c show various embodiments of the body 8 shown in
FIG. 2. It can clearly be seen in FIG. 3a-c that a downstream
widening is provided between the inner wall of the reactor vessel 2
and the body 8. Moreover, the body 8 is open at the top and bottom,
with the result that the treatment agent can be moved downward
again.
[0051] FIGS. 3b and 3c show different embodiments of optional
plates 11, which provide for particular flow profiles of the
treatment agent.
[0052] The person skilled in the art will understand that the
plates 11 may be designed in numerous different ways. It is also
possible for grooves or other means to be used instead of plates,
provided that a favourable flow profile of the treatment agent is
achieved.
[0053] The apparatus according to the invention has been discussed
above merely by way of explanation. It will rapidly become clear to
the person skilled in the art that further features may be
incorporated in the apparatus, for example temperature controllers,
pH controllers, etc., which can be incorporated in the apparatus
according to the invention according to the specific composition of
the water which is to be cleaned. The person skilled in the art
will also understand that the method and apparatus are suitable not
only for removing heavy metals from water which is contaminated
with heavy metals-as has been explained in more detail in
connection with the drawing-but also for any other contaminated
fluid, for example a stream of water which has been contaminated
with organic compounds.
* * * * *